keeyen pang's Posts (28)

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100KM

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We have just completed a pioneer project with Dr Chue Poh Tan from ETH university, Zurich for her postdoctoral research on tropical rain forest biomass estimation with low cost UAV.

Flying in the middle of dense tropical rain forest is very challenging. Looking for a suitable takeoff and landing site is almost "mission impossible". But we are blessed with a team of highly knowledgeable forestry department staff lead by a senior officer. Finally we have two site to lunch the UAV.

I'm using my Skywalker base UAV with the same configuration as this, But I have upgrade it with the APM 2.5 and ublox GPS and 2.73 firmware. The new navigation controller is really amazing. My plane now trace perfectly along the grid line. It also hold altitude better than previous version. I'm totally happy with my current set up and a big thank you for the arduplane development team.

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The real challenge of flying in forest is definitely landing. Although we may have a suitable site for landing but it is all surround by tall trees. The window for approaching is very narrow. Most of the time we have to do a steep dive to lose altitude once the plane pass those tall tree. 

We fly a total of 8 mission in three difference area including one using a modify near infra red camera. There are a few thousands geo-ref image waiting for the Doctor to analyse. I think she will be busy for sometime.

Here I share the tlog from one of the mission and you can see how well the new controller is.

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100KM

UAV Training Program

3689532880?profile=originalSince my last post From Nothing To Landing, some reader interested in my training curriculum. A few reader also point out that education is very important and actually essential to be success in UAV operation.

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Here I share my " home made " UAV training program for a group of six students. They are from the GIS department of a plantation company. 

Day 1

Safety and precaution of radio control electric power UAV system

Introduction to radio control and APM auto pilot

Basic aerodynamic for aeroplane

Introduction to basic radio control plane and flight control

Basic computer simulation training

 

Day 2

computer simulation training

Basic radio control set up

Introduction to radio control flying in auto pilot assisted stabilize mode at STC ( our local flying field )


Day 3

Introduction to Mission Planner

Plan your first mission

Ground control station monitoring

Advance computer simulation training

Traffic pattern flight training

Take off ( hand launch ) and landing practice in auto mode


Day 4

Advance computer simulation training

APM set up and basic PID tuning

Plan and fly mission in hardware-in-the-loop computer  simulation

Traffic pattern at lower altitude

Low pass

Advance radio control airplane flying in manual mode


Day 5

Advance computer simulation training on landing approach

Navigation turning and crosstrack adjustment

Land approach practice in autopilot assisted stabilized mode

These is the general guild line of the training program. we have quite a lot of interaction with the students and sometime we will not follow the guide line but focus on what the students need.   

This training program certainly not endorse by anyone and far from ideal. I just share what I've done and hopefully fellow DIYdroner will trow in their ideas to make the program better.




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100KM

From Nothing To Landing

3689531994?profile=originalLow cost UAV has been advance in leap and bounce in recent year. Today general public can spend a few thousand dollar and a set of fully automatic UAV can be purchase and start taking aerial image and video. At least most of those who selling it hope you"ll to believe this is how simple is it.

Being involve in RC for the last twenty years, we use to spend a few months to help a new RC pilot to earn his wings. Along the way may be a few repair or sometime a few kits are require for the unlucky one.

Today technology has been greatly advance, we have flight simulator, autopilot and so on to help us to complete our flying mission. So is it true that now we can buy a UAV system off the shelf and start using it to get the data that we require ?

Recently I have an opportunity to evaluate if low cost UAV can be integrated to a GIS team of a plantation company. My project is to supply a low cost UAV system, train up a team of GIS executive staffs ( six of them ) to operate the UAV within three training session. Three days per session.

The objective is after the training session, the staffs should able to operate the UAV independently. Because of the restricted open space available in the operation area, and possible wind direction change, automatic landing feature in the autopilot may not a good choice. Manual landing seems mandatory in this situation. So manual landing is one of the our main objective.

The UAV system is Skywalker base with APM and Mission Planner as autopilot and ground control station.

3689532214?profile=originalThe training is divided into four sections. Basic radio control airplane operation, ground control station software training, Flight simulator training and real radio control airplane flight training.

The first two section is relatively easy, Basically the students are introduced with the basic knowledge of radio control airplane, radio control system and related electronic. For ground control station, the students were introduced with the various interface and function of Mission Planner, how to plan a mission, mission monitoring and so on.

The harder parts are the flight simulator and actual radio control airplane flight training. It is easy to say : up elevator.......turn left........level......ect but for a guy who never try radio control airplane, he really do not have the eye-hand coordination require to control the airplane in the air. Another problem is a new RC pilot not use to see the difference position of an airplane in the air.

To help the trainees gain eye-hand coordination as quick as possible, we use flight simulator. Our choice is Realflight 6. It is an excellent flight simulator with great graphic. We start the simulation with the students flying around freely. Very quickly they’ll find it is almost next to impossible to control the airplane to fly in the way they wish. After sometime, I fly a right hand traffic pattern as demo and ask them to do the same.

The simulation training session for each student is 10 minutes. I found that after 10 minutes or so, the student will start to lost concentration and subsequence training time is counter productive.

After a few sessions, all the students had develop some eye hand coordination and able to control the airplane to fly some recognisable traffic pattern but the altitude control is poor. In the evening, I let the students try their hand on my Skywalker with APM under stabilized mode. The reasons to let them fly real RC plane as soon as possible is let them had a feel of how the real things feel and looks while it was in the air. It is to my surprise that all of them can fly the right hand rectangle pattern at three mistake high with verbal instruction. At the end of the first training session, the confident of the students soar as they see for themselves that they can actually fly the plane with guidance.

The next training session is schedule two weeks after the first session. The students are require to practice computer flight simulation during their free time. These two weeks time is design to let the students develop eye-hand coordination. There is really no better way other than time to let the student to develop and acquire the connection and reflex require to fly RC plane.

We meet up two weeks later, now the students has trim down to 4 persons. Two of them really had a hard time to get the plane under control with flight simulator. It is true that everyone can learn to fly RC plane but some may need longer practice.

This session will emphasis on actual flight training with some knowledge of APM parameter and tuning. We go to the flying field as early as 3.00 pm. Arm with the experience acquired from the flight simulator, three of them can fly comfortably with some verbal instruction. Among the three, one of them excel in showing total control of the plane. After a few flight, I let him try some low pass and looks like he can handle it. Other students continue to fly traffic pattern in safe altitude.

In the late evening when the wind was calm, l take the risk and let the good student try to land the plane under stabilized mode. To my surprise he actually able to land it in one piece although he miss the runway. Subsequent flight show that he can land the plane consistently. In the following two days training, all the students can made a landing although some landing approach looks scary, but none of them broke the plane.

Now the training was completed and back to the mission field. Can the students handle the UAV as expected ? I wish to say under my high quality, super efficient training program......bra bra bra......mission accomplished.

Unfortunately the answer is mixed. All of them can plan a mission, set up the camera and assemble the plane ready for mission, but even the best student do not has confident to land the plane in the mission field. The landing area is a small football field surrounded with building and oil palm tree. Therefore in the initial stage, I send an experience RC pilot to help bring the plane down. ( you may guess from the picture who he is )

The students continue their training in the evening after mission flight. Two of them can actually make good landing in calm condition after a few days of hard work. But they still need more practice and experience to become a proficient pilot.

3689532200?profile=originalIn conclusion, I feel that with the help of computer flight simulator, students can master the basic flight technique very fast. But to be able to have total control and made consistence good landing approach and  eventually land the plane really need some time for the skill to develop. We need time to let our eye, brain and hand to communicate effectively and work in harmony.

Finally, Is low cost UAV system plug and play ? I'm sure not quite yet. For a new user to operate our low cost UAV, quality training is very important to ensure safety and effective UAV operation. Some potential user may miss lead by "autopilot" thinking that everything is automatic. I hope anyone who is planning to buy a UAV, regardless if it is low cost or not, quality training should be integrated in the purchase. This, in my opinion, is the most important step toward successful UAV operation.      



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100KM

Techpod review

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Techpod is a special design FPV with hundred of hours of computer calculation and simulation went through during the design stage. With a high aspect ratio glider like wings, it is capable of long flying time. The designer claim for more than 4 hours of flight time with 2 pieces 6S 5000 mah battery in parallel.

I build this plane for aerial photo purpose. I’m looking for a flight time of about 90 minutes. Longer flight time means more battery, thus weight to carry which may affect the quality of flight control.  My current camera ( Canon S100GPS ) battery life may not last more than 70 minutes of continuous shooting at 3 seconds interval.

The build

Kit arrived in double box protection, upon unboxing, I found all the components are neatly pack with plastic bag and no damage. The furnishing of the EPO parts is above average with smooth wings top surface. The fuselage side surface also smooth make this kit looks good.

HobbyUAV web site provide a very detail building video tutorial so I’m not going to repeat here. This is certainly not a beginner kit. Your may face some difficulty if this is your first time building a radio control airplane. If you have some experience under your belt, you’ll good to go.

I highly recommend you watch a few time of the video, lay out all the components and dry fit it to see if you need to sand some parts to get a proper fit. This will also prevent you from fitting the wrong parts at wrong place which is difficult to reverse.

My kit go together well with some sanding here and there. Pay special attention to the T tail structure and make sure the stabilizer is perpendicular to the tail fin.

I don’t like the motor to be permanently mounted to the firewall. I use a motor extension so I can remove the motor easily if needed.

Radio and power set up

Because most of the servo need long extension, It will be a good idea to use heavy gauge (26#) twisted servo wire as your extension wire. If you can do some soldering job, it is good that you make your custom extension wire for neat installation.

You’ll need 6 pieces, preferably digital 9 gram micro servo for all the control surface. You can use a 15 gram mini servo for elevator control if you like it or feel not so comfortable with a micro servo controlling the elevator. I’m using Savox SH 0257 MG with good result.

The recommended motor is Turnigy G10 Brushless Outrunner 810kv but since I have a Turnigy C 4250 700KV motor on hand, may be a little overkill for this plane. I just used it for the initial test flight. I’ll change to some dish type motor like T Motor 4008 340KV in the future. Speed control is 50 A Turnigy ESC. I’m using a external BEC ( CC 10 A BEC ) to supply current for the electronic. The build in BEC from the ESC may not able to handle those long servo wire. An APC 12x6 propeller and 4S 5000mah battery finish the power package.

Wings hold down modification

The default wings hold down method is by clamping the center section with two pieces thick plywood and a long screw. I don’t have much confident with it so I do a simple modification as shown in the picture. Now I’m sure the wings will not give way in any flying condition. The modification is quite simple. I cut two lengths of plastic tube, cut off some foam and glue them into the wings as shown in the picture. Next I insert a 3 mm music wire into one end of the tube, tap and use a 3 mm screw to secure it permanently. The opposite site also use a 3 mm screw but it will be removable  After I plug in the wings, I can secure the wings with the screw from outside.  I have to stretch that the default method should work well as per design, this is just my personal opinion to make it feel more secure.

Test flight

After about two week on and off building, now the moment has come to test flight the plane. As a radio control airplane hobbyist, we always get excited whenever we fly a new plane for the first time.

Double check all the control surface, CG and all wiring connection, a fellow RC buddy lightly toss it into the winds while I have about 70 % throttle and a little up elevator. The plane climb up with authority at this throttle setting. Once reach about 100 meter altitude, I bring it to the end of the runway, make a procedure turn and do a straight and level flight to trim the aileron and elevator.  I just need “some” trim and I am able to let it flying straight and level hands off. The elevator control feel solid and very responsive but the aileron control  feel a little sluggish. I think this is due to the fact that it had a long wingspan. The response of the aileron input is a little slow especially when I want to level out the wing from turning. At time I had to apply full counter input to bring the wing back to level. On subsequent flight I increase the ATV of the aileron and it responds better.

Landing the Techpod is very easy, it has a very good glide ratio and also very graceful low speed handling. Just set up the final approach about 150 meter away and into some head wind with altitude about 50 meter, the plane will glide down gracefully , you may control the descent rate with small throttle input.

For those of you who never fly a sail plane, you may not comfortable to see the wings “ flap “ during flight. The designer had assured us that the wings is plenty strong and the flapping action of the wings is by design. He had a video to show just how strong and flexible the carbon wings tube is.  

One must remember that this is a FPV plane, not a pylon racer. It will NOT handle high speed, high G maneuver well and may cause flutter. Don’t ask me how I discover this.... : ) but I can tell you my plane is still flying.

Overall, I am very satisfy with the performance of the plane in full manual mode. No significant bad habit show up in the test flight. I am also confident that with a proper size motor, the plane will fly equally well in auto mode.

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100KM

NewSkywalker follow up

 

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As Prof LianPin Khoo post an interesting 3D amination here and also here . Someone is interested to see more picture of the plane which capture those images.

I have a blog which show the basic info about the NewSkywalker. Now I have get it set up properly and adjust some APM parameter base on my previous Skywalker1900. I also have flown a few mission with it and quite happy with the performance and the ability of APM to hold proper grid line in windy condition. During the test flight, I also had an unplan " durability" test where it fall from about 30 meter because of the receiver battery voltage went low. This is my own fault because I forgot to get it fully charge. I actually did check with the voltage before flight and it show sufficient. It survive the crash with some crack in the nose area and a wings broken about 10 inches from wing tip. Some EPO glue and fiberglass tape had it repair in no time and it have flown another few mission subsequently.

The only modification I made is cut a hole as shown in the picture for camera. Now my camera can fix inside the fuselage nicely with proper orientation. I'll put the camera nearer to the nose for my next Newskywalker because with the current location, I had to add about 160 gram of weight in the nose to balance it. The vibration dampen foam is a piece of air conditional copper pipe insulator. This idea is given by Prof LianPin Khoo and it work. I also cut a door at the left fuselage similar to old version skywalker for ease of access to the battery and other electronic on board

With the set up as describe in my previous blog, I can have about 30 minutes time with 40 % throttle cruise setting. At the end of the flight, I still had about 1000 mah reserve in the battery. For my typical aerial mapping mission. I'll normally fly at 200 meter altitude. In 20 to 30 minutes it'll cover 200 Ha of land with 60 % overlapping area.

The next trial will be 10000 mah 4S ( 2x 4S 5000 mah ) endurance test. I hope it'll able to fly for 50 minutes. 

 

 

 

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100KM

New Skywalker 1900

3689504751?profile=originalThe New Skywalker 1900 has been around for sometime. I just finish mine and test fly it last Sunday in strong wind condition. I barely able to trim for straight and level and P gain in stabilized mode.

It feel more or less like my old Skywalker 1900 but the rigidity of the tail section had been much improve. No more flimsy/Shacking tail boon and stabilizer.

Although it was advertise as modular/easy to dismantle and install  at field, but I doubt the durability of those orange plastic. For better reliability, glue the stabilizer and tail boom may seems a good option.

For me, the best improvement over the previous version is the enlarge fuselage. Now I can put my camera inside the fuselage with proper orientation. ( Horizontally relative to wings ). The only issue is now I had to add about 90 gram of ballast in the nose for proper CG because of the main battery sit right under the wings with no room for CG adjustment. 

A lot of user reported the left turning tendency but I didn't notice mine had this problem. Some of them suggested a twisted wings but if that is the case, than most properly all the wings should be the same because it was made in the same aluminium mold. May be I just lucky to get a good set of wings.

Nothings much to talk about the build. It is fairly simple and straight forward. I had good success with my old Skywalker so I just transfer all my equipment, i.e motor, ESC, APM 2 with 2.63 firmware to the new one. For telemetry, I use RDF900. Hopefully with this long range data modem, I'll had full connection through out the mission within a few KM.

I'll update the flight performance after I had it trim out. My flight gear as below:

Servo : Servox SH0257MG

Motor : T motor 2814-8 1000KV

Prop : APC 9X6

ESC : Hobbywings Funfly 60 A

Autopilot : APM 2. 2.63

Telemetry : RDF 900

Battery : FlightMax 4S5000mah. for motor. 2S 2100mah for avionic equipment regulated by Castle Creation 10A BEC

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100KM

Formation flight with an eagle.

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I was testing my Maja in full manual mode this afternoon, an eagle come and join the fun of it. We flew a few round together before I realise that it actually come to defends it's airspace. A few attempt to close in with the plane and lower it's craw ready for a catch. Lucky it didn't success and I have power reserved to escape from situation. 

MY Maja 2.2 M was build as per instruction with some reinforcement. AUW is 2.8kg. A 3S 2200 battery was put in front as ballast. CG set at 75 cm from leading edge. Currently just basic RC gear without FPV equipment and telemetry. For aerial mapping purpose, I'll expect the AUW to be 3 to 3.1 KG. 

Using the Motor and ESC supplied with the kit spinning a 12 x 6 propeller, it had lot of power for easy hand lunch. I did not experience any pitch down problem during hand lunch as reported by some pilot. Just a gentle toss and it is up on its way. By the way, my battery is 4S 5000 mah.

The current configuration make the plane feel stable in roll axis but sensitive in pitch. Initially I had some difficulty to handle it because it'll pitch up quite severely and slow the plane down during level out from a turn or facing some head wind. A lot of us just can't feel comfortable to push down elevator for normal flight.

The plane glide well but keep an eye on the airspeed because of the pitch up problem. down elevator is needed to maintain safe landing speed.

I think APM will smooth out the pitch up issue. Will try it when the casing I order from 3DR shop come.3689499738?profile=original  

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100KM

First aerial mapping trial

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After a few months of trial and error, I finally figure out the basic of aerial mapping. Blessed with good weather two days ago, I took out my Skywalker 1900, APM 2 equip with Canon S100 to a near by oil palm estate own by a friend. The Skywalker with my current param track extremely well even in strong cross wind condition. 

The total flight time is about 30 minutes from take off to landing covering 320 Ha of land at 300 meter altitude. The cross line distance is 140 M and the camera CHDK set to release shuttle every three seconds. 

One interested things I discover is the GPS location shown in the mission planner is about 160 m away from the google map. 

From the total of 500 plus images taken, I trim down to 89 image and put it through Autopanogiga. ( mine is trial version so water marks appear ) and the result is quite promising. I'm new to this program so the image is all run by the program default settingwithout manual intervention. It may able to provide better result if I gain more knowledge with it.

My Skywalker is build base on much of the information @ http://conservationdrones.org/

For those of you who wish to view the original file, here is my dropbox link https://dl.dropbox.com/u/35844265/%5BGroup%201%5D-Sandajaya300M%20110_Sandajaya300M%20513-89%20images%20%282%29.jpg

 

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